Plots.contour rounding the contour labels

selvi-aras · June 28, 2023, 4:39pm

I am using Plots.jl to generate a contour plot. It works great but the contour labels have 5 digits after the decimal point:

How can I update my code, which is shared next, so that the contour labels are rounded to decimals? I looked into this for a while, and there is no easy way so far. I would prefer an option that does not use any other visualisation package than Plots.jl. Thank you.

x_ran = range(-4, 2.0, length=600)
y_ran = range(-1, 2.5, length=600)
z = @. eval_f(x_ran', y_ran)
Plots.contour(x_ran, y_ran, z, levels=15, 
        color=:acton, xaxis = (L"x_1",font(10)), 
        yaxis = (L"x_2", font(10)), clabels= true,
        title = "contour plot",
        cbar=false, lw=1, 
        xguidefontsize=14, yguidefontsize=14)

rafael.guerra · June 28, 2023, 6:23pm

For your example, try passing to contour() the keyword argument:
levels=4:13

selvi-aras · June 29, 2023, 8:44am

Thanks! Good hack!

sdanisch · July 13, 2023, 9:28am

In Makie you can pass a labelformatter:

using CairoMakie, Printf
using Makie.LaTeXStrings
eval_f(x, y) = cos(x) * sin(y)
x_ran = range(-4, 2.0, length=600)
y_ran = range(-1, 2.5, length=600)
z = @. eval_f(x_ran', y_ran)

contour(x_ran, y_ran, z, levels=15,
    labels=true, labelformatter=(x) -> @sprintf("%.1f", x),
    colormap=:acton, axis=(xlabel=L"x_1", ylabel=L"x_2", title="contour plot"),
)